Copernicus DEM 30 support (JRC-1)

[kautlenbachs]

Check BaseElevationModel.java from SNAP project. Everyhting should start to unwind there. So for example based on SNAP structure:

• ElevationModel.java interface (there are APIs that are needed during processing)

• Base class for inheritance is BaseElevationModel.java

• Then comes CopernicusElevationModel.java for example that inherits from previous

• Then there are BaseElevationTile and ElevationTile

• First lets refactor the current SRTM3 support and then test if the results remain the same, then lets implement support for others.

Bonus: Would be nice if we'd get rid of continous resampling as done in GetElevation(), if this would be done once on GPU, things would be much faster. Following stuff:

• snapengine::bilinearinterpolation::ComputeIndex()
• snapengine::bilinearinterpolation::Resample()

[kautlenbachs]

Terrain correction operator support done. Example from calibration routine (bel ger flood)

[kautlenbachs]

Another example (maharashtra)

[kautlenbachs]

For coherence, the backgeocoding support has been introduced, but there are something off - the results are empty (For Copernicus DEM). There are three kernels where DEM is used:

• Burst offset
• Elevation mask (can be switched off, probably not a source of error)
• Extended amount
• Slave/secondary pixel position (most sophisticated one, probably source of error)